1. Field of the Invention
The present invention concerns a gassing incubator for cultivating human and animal cells or tissues. More particularly, this invention concerns incubators having an inner case which can be closed by an outside door. This inner case is surrounded by a thermally insulating outer case, the outer case being spaced away from the lateral walls, rear wall and roof of the inner case. Electrical heating elements are disposed under the floor of the inner case and in the lateral wall area. The incubator also has a means for humidifying the internal atmosphere
2. Discussion of Related Art
An incubator of this kind is disclosed, for example, in GB-A No. 231,259. Between the inner case and the outer case a one-piece tubular heating element is disposed which runs in a serpentine configuration through the two side walls and the floor. Both the walls and the floor of the inner case have openings through which the air in the interstitial space, heated by the tubular heating element, can circulate into the incubating chamber. The air flow between the central or incubating chamber and the interstitial space is produced by a blower in the rear wall which aspirates the air from the central chamber into a chamber at the rear of the incubator and returns it to the interstice through a bottom chamber. The central chamber can also be connected by an air duct to a refrigeration unit which has an additional blower as well as an evaporator.
To moisten the air in the central chamber of such incubators, two different kinds of humidifying means are used. In the one kind, water is evaporated from a water reservoir outside of the central chamber and the aerosol is fed to the central chamber. Another way of humidifying the central chamber air is to place a water reservoir directly in the central chamber where it is evaporated. Usually, a water pan is disposed on the floor of the central chamber and heated with an appropriate heating device which ca be placed directly in the water bath.
It is to be observed that the known incubators achieve widely varying results in regard to uniform temperature distribution along the inner walls of the incubator chamber. For example, incubators in which the temperature distribution in the inner case is irregular tend to form condensate on the colder areas of the wall, so that high humidities of 90% and up are very difficult to achieve.